Yongnuo ONLY firing at full power?

Hello,

Anyone have this happen to them?

One of my Yongnuo 560 III's started to only fire at full power. Everything was working normal, until my last shoot. I was setting up a shot and needed to lower the power on one side, and I lowered it to 1/128 and saw that there was no difference between that and 1/1. I use a TX560 controller, if that means anything. I tried switching it to different modes (slave, manual, remote), and no luck. Replaced the batteries and no dice.

Kind of strange for it to randomly start doing this, but I guess for a $60 flash I shouldn't expect any better?